Head circumferences standards in neonates.

Head circumference at birth is an important measure of intrauterine growth, reflecting accurately brain growth and predicting subsequent development. Standards need to reflect the population and the factors that affect intrauterine growth in the population and must be constructed in a manner that is clinically useful and predictive. Many of the present standards used to assess newborn infants are inadequate because of the limitations of sample size and study design. As a result, the current standards are not adequate for premature infants below 30 weeks of gestation and, in newborns from later in gestation, may underreport significant deviations from the mean in certain situations.